Answer:
Josh is the strongest
The net force is 5N towards right
I dont know what the statements are but concave lens are thinner in the middle which cause light to diverge or scatter
The force of attraction between two objects can be illustrated using Newton's Law of Universal Gravitation.
The relation between the different parameters is shown in the attached image.
Now, from the relation, we can deduce that the force between the two objects is directly proportional to the masses of the two objects.
This means that, if the mass of one object is doubled, then the force between the two objects will also be doubled.